Changeset b281379

Timestamp:

Oct 22, 2003, 4:27:44 PM (21 years ago)

Author:

jtwang <jtwang>

Branches:

master, debian, mac, no-cups, nodebathena, web

Children:

6761cd4

Parents:

bc5ca87

git-author:

jtwang <jtwang> (10/22/03 16:27:44)

git-committer:

jtwang <jtwang> (10/22/03 16:27:44)

Message:

Correct security problems with $uri being passed on the command lines
to w3m, mpg123, and ogg123, all of which via /bin/sh, and thus subject
to shell expansion, especially of shell metacharacters.

Replace them with open("-|") fork-exec machinery. Note that this
eliminates a previously required temporary file for mpg123/ogg123
output, but at the cost of some code-complexity. Perhaps the common
parts of the mpg123/ogg123 invokation should be factored out.

(log message from jhawk)

File:

• gutenbach/debian/lib/sipbmp3-filter (modified) (4 diffs)

gutenbach/debian/lib/sipbmp3-filter

@@ -2 +2 @@
 # Play the data on STDIN as an audio file
 #
-# $Id: sipbmp3-filter,v 1.8 2003-08-11 02:11:28 jhawk Exp $
+# $Id: sipbmp3-filter,v 1.9 2003-10-22 20:27:44 jtwang Exp $
 # $Source: /tmp/tmp.UFBNno9997/RCS/sipbmp3-filter,v $
 #
@@ -145 +145 @@
       if (<STDIN> =~ /^(\S*)\s*(.*)$/) {
           $uri=$1;
-          open(W3M, "/mit/sipb/bin/w3m -dump_head $uri|");
-          $contenttype="unknown";
-          while (<W3M>) {
-              if ($_ =~ /^Content-Type:\s(\S*)/) {
-                  $contenttype=$1;
+          my $pid = open(W3M, "-|");
+          unless (defined $pid) {
+              print ZEPHYR "Couldn't fork: $!\n";
+              close(ZEPHYR);
+              return;
+          }
+
+          if ($pid) { #parent
+              $contenttype="unknown";
+              while (<W3M>) {
+                  if ($_ =~ /^Content-Type:\s(\S*)/) {
+                      $contenttype=$1;
+                  }
               }
-          }
-             if ($contenttype eq "audio/mpeg") { $format="MP3" }
-          elsif ($contenttype eq "application/x-ogg") { $format="OGG" }
-          elsif ($contenttype eq "application/ogg") { $format="OGG" }
-          else {
-              print ZEPHYR "Unknown Content-Type $contenttype for URI $uri\n";
-              close(ZEPHYR);
+              if ($contenttype eq "audio/mpeg") { $format="MP3" }
+              elsif ($contenttype eq "application/x-ogg") { $format="OGG" }
+              elsif ($contenttype eq "application/ogg") { $format="OGG" }
+              else {
+                  print ZEPHYR "Unknown Content-Type $contenttype for URI $uri\n";
+                  close(ZEPHYR);
+              }
+              close(W3M) || print ZEPHYR "w3m exited $?\n";
+          }
+          else { # child
+              exec("/mit/sipb/bin/w3m","-dump_head",$uri) || die "Couldn't exec";
           }
       } else {
         print ZEPHYR "Couldn't read URI for external reference\n";
         close(ZEPHYR);
-      }
+    }
   } else {
       print ZEPHYR "Unknown syntax in play_external_reference(): $magic\n";
@@ -207 +219 @@
   system("ps ax | grep mpg123 | awk '{print $2}' | xargs kill -9");
   system("chmod a+rw /dev/audio");
-  system("/mit/infoagents/bin/mpg123 -b 16384 -q $up $uri >/tmp/mpg123.out 2>&1");
-
-  # Done. Status:
+
+  # Prepare to write status:
   open(ZEPHYR, '|/usr/athena/bin/zwrite -d -n -c sipb-auto -i sipbmp3@xcb -s "SIPB LPR music spooler"');
-
-  # Check if there were any errors
-  open(MP3STATUS, "/tmp/mpg123.out");
-  if ($_ = <MP3STATUS>) {
-    print ZEPHYR "Playback completed with the following errors:\n";
-    print ZEPHYR $_;
-    while (<MP3STATUS>) {
-      print ZEPHYR $_;
-    }
-  } else {
-    print ZEPHYR "Playback completed successfully.\n";
-  }
-  close(MP3STATUS);
-  unlink(MP3STATUS);
-
-  close(ZEPHYR);
+      
+  # fork for mpg123
+  my $pid = open(MP3STATUS, "-|");
+  unless (defined $pid) {
+      print ZEPHYR "Couldn't fork: $!\n";
+      close(ZEPHYR);
+      return;
+  }
+  
+  if ($pid) { #parent
+      # Check if there were any errors
+      if ($_ = <MP3STATUS>) {
+          print ZEPHYR "Playback completed with the following errors:\n";
+          print ZEPHYR $_;
+          while (<MP3STATUS>) {
+              print ZEPHYR $_;
+          }
+      } else {
+          print ZEPHYR "Playback completed successfully.\n";
+      }
+      close(MP3STATUS) || print ZEPHYR "mpg123 exited $?\n";
+      
+      close(ZEPHYR);
+  }
+  else { # child
+      # redirect STDERR to STDOUT
+      open STDERR, '>&STDOUT';
+      exec("/mit/infoagents/bin/mpg123","-b16384","-q",$up,$uri) or die "Couldn't exec";
+  }
 }
 
@@ -407 +431 @@
   system("ps -aef | grep ogg123 | awk '{print $2}' | xargs kill -9");
   system("ps -aef | grep mpg123 | awk '{print $2}' | xargs kill -9");
-  system("/mit/sipb/bin/ogg123 -b 40000 -dau -q -f - $uri 2> /tmp/ogg123.out | audioplay");
-
-  # Done. Status:
+
+  # Prepare to write status:
   open(ZEPHYR, '|/usr/athena/bin/zwrite -d -n -c sipb-auto -i sipbmp3@xcb -s "SIPB LPR music spooler"');
 
-  # Check if there were any errors
-  open(OGGSTATUS, "/tmp/ogg123.out");
-  if ($_ = <OGGSTATUS>) {
-    print ZEPHYR "Playback completed with the following errors:\n";
-    print ZEPHYR $_;
-    while (<OGGSTATUS>) {
-      print ZEPHYR $_;
-    }
-  } else {
-    print ZEPHYR "Playback completed successfully.\n";
-  }
-  close(OGGSTATUS);
-  unlink(OGGSTATUS);
-
-  close(ZEPHYR);
-}
-
+  # fork for ogg123
+  my $pid = open(OGGSTATUS, "-|");
+  unless (defined $pid) {
+      print ZEPHYR "Couldn't fork: $!\n";
+      close(ZEPHYR);
+      return;
+  }
+  if ($pid) { # parent
+      # Check if there were any errors
+      if ($_ = <OGGSTATUS>) {
+          print ZEPHYR "Playback completed with the following errors:\n";
+          print ZEPHYR $_;
+          while (<OGGSTATUS>) {
+              print ZEPHYR $_;
+          }
+      } else {
+          print ZEPHYR "Playback completed successfully.\n";
+      }
+      close(OGGSTATUS) || print ZEPHYR "ogg123 exited $?\n";
+            
+      close(ZEPHYR);
+  }
+  else { #child
+      # redirect STDERR to STDOUT
+      open STDERR, '>&STDOUT';
+      exec("/mit/sipb/bin/ogg123","-b40000","-dau","-q","-f","-",$uri);
+  }
+}
 
 # Play an OggVorbis audio file